This is a blog about the Four Corners area of Silver Spring, Maryland. I write about all things affecting Four Corners; such as local news, events, people, places, and history. For the purposes of this blog, Four Corners is bounded by Northwest Branch & Sligo Creek to the East and West, and Northwood & Wayne Avenue to the North and South. Hope you enjoy the blog!

Monday, July 18, 2016

Crossing Beltway ramps could be safer

If you've ever driven to the College Park Ikea on the Beltway from around here, you've used the ramp from I-495 to U.S. Route 1 north. While that cloverleaf ramp in College Park may seem mundane, there is something interesting about it.

Despite the presence of a generous merge lane from the ramp onto Route 1 northbound, many drivers stop at the top of the ramp, and most slow down significantly. Why slow down (or stop) if there's plenty of room to merge onto Route 1? Why not just continue at 30 or 40 MPH off the ramp and onto the road? This seemingly inconsequential highway off-ramp can teach us quite a bit about pedestrian safety at highway interchanges.

The ramp where it meets Route 1. Despite the merge lane, most drivers stop or slow down before entering Route 1. Photo by the author.

The reason so many drivers stop or slow down as they exit this ramp onto Route 1 is the angle at which the ramp meets the road. In the mid-2000s, as part of the Ikea project, the State Highway Administration (SHA) wanted to create more merge room for motorists merging northbound onto Route 1 from the Beltway, to both improve access to the store and improve traffic flow on this part of Baltimore Avenue.

The SHA sought to minimize what traffic engineers call "weaving", where motorists merging onto a highway use the same lane as those exiting the highway. Weaving is found at all cloverleaf interchanges, as it is inherent in their design, and it is the reason why cloverleafs are rarely built anymore. Where cloverleafs do exist, often times the solution to weaving is to reconstruct the interchange, but the SHA didn't have space or funding for that here. Instead, they added about 200' of merge room by making the off-ramp more of a right angle than the sweeping curve it used to be.

The ramp (at center) in 2002. Image from the U.S.. Geological Survey.

The ramp in 2007, after being rectified. Image the from U.S. Geological Survey.

When the SHA altered the ramp to provide merge space, they inadvertently improved pedestrian safety at the ramp's crosswalk. Because the ramp has a tighter turn, most drivers slow down significantly to make the right. Some even stop, since the angle of the ramp leads those unfamiliar with the area to assume they don't have a merge lane (merge lanes are rarely found after "hard right" turns, so it's quite rational to come to a stop at such a turn). This reduced speed makes the crosswalk safer and more comfortable for pedestrians, since drivers behave as if they are turning onto a street rather than merging onto a highway.

Now, I've just explained that this project was carried out solely to add more merge room for motorists. Pedestrian safety was not the purpose of this realignment (if it was, they would've actually built a continuous sidewalk instead of having it arbitrarily end just south of this spot). However, what if the SHA did do projects like these for pedestrian safety?

A driver exiting the Beltway slows for the turn onto Route 1. Photo by the author.

Here in Four Corners. we have two Beltway interchanges with crosswalks across each ramp. Since these crosswalks are the only way to walk between neighborhoods inside and outside the Beltway, they get decent usage. They are heavily used by Eastern and Blair students, given the proximity of those two schools to the interchanges. Unfortunately, the crosswalks at our Beltway ramps are really dangerous too.

The ramp from Route 29 north to I-495 east. Photo by the author.

With the exception of an off-ramp at University Blvd which was reconfigured in 2007, the ramps connecting the Beltway to Colesville Road and University Blvd date to the late 1950's. They were never safe to begin with for anyone except motorists, and now they're both unsafe and antiquated. The sight-lines are poor at many of these ramps due to vegetation and the sweeping curves designed for speed. Take, for example, the ramp from Route 29 north to I-495 east (pictured above). Between the trees and the gradual curve, pedestrians waiting to cross can barely see oncoming cars until they're very close. Since most drivers here are focused on getting on the Beltway and accelerating, pedestrians have to dart across and hope no one's coming around the bend.

Ramp from I-495 east to Route 29 north. This type of highway geometry is inappropriate for traffic entering a pedestrian environment next to a large high school. Photo by the author.

There's nothing wrong with designing for speed in an auto-only environment (such as an interchange between two interstate highways), but designing for speed at an interchange between an interstate and a local road with bikes and pedestrians is just preposterous. Designing a ramp conducive to speed is important for a motorist merging onto a limited-access highway with free-flow traffic. However, motorists do not need speed to merge onto an arterial road containing pedestrians, cyclists, and traffic signals.

If anything, motorists entering a local road should be slowed as much as possible to adjust them to the different driving environment in which they find themselves (interstate driving is much different than arterial road driving, since arterials like Colesville Road have far more variables than an interstate like the Beltway).

While absurd pedestrian conditions currently exist at the Colesville and University interchanges, they can be easily mended by doing what the SHA did to the Beltway ramp at Route 1.

I-495 west to Route 29 north. The road design tells drivers to go fast, but the crosswalk expects them to stop. It's a no-win situation for drivers and pedestrians. Photo by the author.

If the SHA would reconfigure all of these ramps to have tighter corners where they meet the arterial roads, rather than the gradual bends they currently have, it would drastically improve pedestrian safety. I drew a quick mock up in Google Earth of what such a reconfiguration of the ramps could look like at Colesville Road and the Beltway, seen below. Hopefully this will help visualize how easy this could be to make this common sense safety improvement.

This is what is looks like today. Image from Google Earth.

This is what it could look like if realigned. Drawn by the author, base image from Google Earth.

This is the type of small but meaningful project that the SHA can and should pursue to make a real impact on pedestrian safety and the walkability of this community. Flashing lights and pedestrians signs simply don't convey the same "slow down" message that a tight corner does. I see no reason why these realignments couldn't be done. The SHA already owns all the land they would need (no acquisition costs), and the fact that they've already implemented it elsewhere in their 3rd District shows that such realignments meet their standards for turning radii, etc. Given the fact that realignments such as these require minimal grading and paving work, I doubt it would cost much either, especially when compared to something like the Georgia & Randolph interchange project.

This is a common sense solution to a longstanding problem, and we as a community should push the SHA to make this commitment to pedestrian safety.

13 comments:

How do we suggest such changes to SHA? During the bridge rebuild (which is almost done, thankfully) it was even more dangerous for our high school students. Cars on West bound Univ entering the outer loop of 495 rarely stopped at the red light. And it is even worse when cars exiting the inner loop to go East bound on Univ where for the past two years they had their own lane and now they don't. Most don't realize it till it is too late and that is just for avoiding hitting cars, much less pedestrians which again are mostly high school students. Complaints to both SHA and Blair High School went no where for the last two years during the bridge project. And don't get me started on the snow covered sidewalks that are impassable along the bridge span either. I am very interested where you go with your ideas and hope it gets some attention.

Thank you. These crossing are so hazardous and really need improvement. I regularly bike or cycle through them and inevitably 10-20 cars blow right past me as I wait to cross. Half may not see me and the other half are the sort who don't believe in or understand what pedestrian crossings are for. Even worse when you cross where you can't see the oncoming traffic until you are right at the crossing.

My son is in middle school at St.Bernadette's and we live in the Indian Spring neighborhood. I have to pay for after care because it's too dangerous to let him walk home alone over those interchanges.I'd love to see these changes take place and will support the cause if pursued. I was told there was once discussion of a pedestrian bridge over the beltway at University but that did not receive enough support. I believe it was years ago when the suburbs were more car-centric.

One consideration of slowing vehicular entrance to Colesville Road is the likelihood of creating backups onto the Beltway's right lane during evening rush hour, which might substitute one danger for another.

Definitely something to consider, but I'm not sure it would be an issue. There would be at least 1000' between the start of the merge lane on the Beltway and the top of the ramp at Colesville under my proposal, which is plenty of space for vehicles to queue if need be. Since there's no light at the top of the ramp, I see no reason why a large queue would form. As bad a Route 29 traffic can get, I have never seen this off ramp back up all the way onto the Beltway due to Route 29 congestion in all my years living here. While the tighter turn would cause vehicles to slow down more, I doubt it's presence would be enough to create such a large back up. Thanks for reading!

It would help if the sidewalks were kept clear and free of debris. I often walk from the YMCA area to Safeway / PO / and the bank. I'm often amazed at how little pride the business community takes in the entire area, especially the Shell across from McD's. I quit going there just for this reason. With respect to crossing the beltway, I've not had a problem, but you have to be realistic and understand that most drivers will not stop for you, crosswalk or not.

I agree with keeping sidewalks clear. My guess as to why the businesses don't show pride in keeping unobstructed is that they assume most of their customers arrive by car (and that's probably true), so pedestrians are an afterthought.

Regrading cars stopping at crosswalks, I understand that most drivers won't stop, but should we really tolerate that? Stopping for a pedestrian is one of the smallest inconveniences a driver can encounter on their trip (the true inconvenience to drivers comes from all the other drivers on the road getting in each other's way). I don't think we should accept a culture where well thought-out laws intended for the safety of vulnerable road users (pedestrians don't come with bumpers and air bags) are disregarded en masse.

The solution is physical realignments such as the ones I propose in this piece, and better training of and enforcement by the Montgomery County Police and Maryland State Police.